Problem: $9ab + ac + 6a - 6 = 7b - 5$ Solve for $a$.
Explanation: Combine constant terms on the right. $9ab + ac + 6a - {6} = 7b - {5}$ $9ab + ac + 6a = 7b + {1}$ Notice that all the terms on the left-hand side of the equation have $a$ in them. $9{a}b + 1{a}c + 6{a} = 7b + 1$ Factor out the $a$ ${a} \cdot \left( 9b + c + 6 \right) = 7b + 1$ Isolate the $a$ $a \cdot \left( {9b + c + 6} \right) = 7b + 1$ $a = \dfrac{ 7b + 1 }{ {9b + c + 6} }$